Eastern Europeans face a bewildering variety of new laws effective Jan. 1 as part of their governments' attempts to get stagnant economies moving again.

In Hungary, which has taken a leading role among East Bloc countries in implementing the kinds of economic reforms advocated by Soviet leader Mikhail Gorbachev, a new customs law is expected to draw a stampede of 30,000 to 50,000 used Western cars into the country in 1989.The law allows Hungarian citizens to import Western-made cars less than 4 years old for a duty of only 10 percent of the "blue book" price as determined by the Eurotax-Schwacke car price catalogue. The cars must have engines of less than 1,600 cubic centimeters for gasoline-fueled cars and 2,000 cubic centimeters for diesel makes.

Poles, who have endured numerous cycles of price increases in the past decade, usher in the New Year with another round of hikes led by new-car price increases that in some cases more than doubled.

The sporty Polish Polonez, for example, will go up from 2.5 million zloties ($5,000) to 7 million zloties ($14,000), an increase of 180 percent.

Gasoline will no longer be rationed, for the first time in nearly eight years, but Poles must pay for the privilege - in the form of a 58 percent price hike. Diesel fuel also is going up, as are rates for telephone and postal services and radio-television monthly fees.

The government added the proverbial lump of coal in the stocking this weekend by increasing the cost of international telephone calls by an average 65 percent - retroactive to Dec. 10 to catch tens of thousands who telephoned relatives in the West for Christmas.

On Saturday night, after strong criticism of the move in the Communist Party newspaper Trybuna Ludu, Prime Minister Mieszyslaw Rakowski ordered the higher rates annulled until Jan. 1 and ordered disciplinary measures against "those who were to blame for such a vivid disregard for citizens," the official news agency PAP said.

Several major banking and economic laws go into effect in Poland, Hungary and Czechoslovakia aimed at making it easier to invest and do business in those countries, where the economies are in a shambles due to decades of tight economic control by the Communist Party.

In Yugoslavia, a radical economic reform package is supposed to go into effect Sunday. But the government resigned Friday, and no one knows what is going to happen in the communist but non-aligned nation, which is struggling with unemployment, increasing labor unrest, 250 percent inflation and a $21 billion in foreign debt.